Indicators of training effects in endurance race include VO₂max. Measurement of VO₂max is not easy because it requires a research facility. Therefore, simple estimation methods have been investigated. They include the Åstrand and Ryhming nomogram, which allows the estimation of VO₂max from heart rates and VO₂ during submaximal exercise. However, since it was developed for those in 20s, it lacks accuracy in estimating VO₂max in 30s or older with lower maximum heart rates. In recent years, wearable wristwatch-type equipment with sensors, such as GPS, have been widely used, facilitating the measurements of heart rates and running speeds during exercise. Therefore, if VO₂max can be estimated from running speed, it can be conveniently measured simply by wearing wearable equipment and using the Åstrand and Ryhming nomogram. In addition, the above issue relevant to the Åstrand and Ryhming nomogram can be solved by taking the maximum heart rates of individuals into consideration, allowing the estimation of VO₂max close to the actual measurement. Therefore, we aim to examine whether VO₂max can be estimated from heart rates and running speeds during running using the Åstrand and Ryhming nomogram by taking the maximum heart rates of individuals into consideration. Thirty-five healthy men (age: 36.7 ± 12.7, height: 170.0 ± 5.1 cm, body weight: 65.8 ± 7.3 kg) and twenty-eight healthy women (age: 37.4 ± 11.8, height: 158.8 ± 5.3 cm, body weight: 51.3 ± 5.3 kg) were included. For each subject, running speeds and heart rates were measured using low-, medium-, and high-intensity constant load tests after measurement of VO₂max and maximum heart rates by an incremental load test. VO₂ was estimated from the running speeds using the ACSM running equation. VO₂max was estimated using the formulated VO₂max estimation nomogram of Åstrand et al., and compared with the VO₂max measured in the incremental load test, demonstrating a significant correlation between the measured and estimated VO₂max in both males (r = 0.81) and females (r = 0.75) (p < 0.01). In conclusion, the novel Åstrand and Ryhming nomogram is applicable to wearable equipment by taking the maximum heart rates of individuals into consideration and using running speeds and heart rates during running.

  We have developed a thin digital running watch. Set 4 points to improve basic performance. (1) Wearability (2) Easy to see (3) Long-term use (4) Easy to use. The product was realized by developing elements such as the size and thinness of the movement, display, button layout, and power supply. Then, through hearings with runners, we worked to improve the usability of the product.

  In this chapter 1, the fundamental equation of vibration for the free damped case and its power consumption are described. The consumption power of the balance-spring system should be regarded as the solid friction resistance of the pivot of the balance staff and the viscous resistance of balance-wheel rotating in the air. Moreover, the relationship between the Q value which represents the goodness of the vibration system and the frequency of vibration, effect of high vibration frequency and the improvement of wearing accuracy are described. In chapter 2 in the next book, basic theory of isochronism, the nonlinearity portion of hairspring action. In chapter 3, explanation of isochronism of horizontal positions, mainly based from the outer end fixation of hairspring. In chapter 4, explanation of the isochronism of vertical positions based on the unbalance moment of inertia of balance-wheel and the inner terminal fixation of hairspring. Weighing method of middle place of hairspring is explained here.